Film image not focusing on left side

Discussion in 'Medium Format Cameras and Accessories' started by jtcliff, Dec 9, 2012.

  1. jtcliff

    jtcliff Subscriber

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    I have been testing out a Perkeo 6x6 folding camera. At infinity setting I am getting the center of the negative sharply focused. However, the left side is blurry. See example attachment. This fuzziness is less apparent in shots focused 60 ft or less.
    I have tried measuring the parallelism of the lens and the back film rollers and, within my accuracy limits, they seem OK. The lenses are clean and very clear.

    Any suggestions?
     

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  2. George Collier

    George Collier Member

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    Looks like the film is not flat at the exposure plane. I don't know this camera, but can you open the back (or remove the lens), load (sacrifice) a roll of film, advance it across the exposure opening, and see if it is flat?
    If it looks like most folders I've seen, the image would be upside down, so the problem would be on the leading (take-up) side of the film, yes?
     
  3. Sirius Glass

    Sirius Glass Subscriber

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    Look for the problem on the right side of the lens from the back of the camera. The image is flipped around: top on bottom, bottom on top, right on left, left on right.
     
  4. George Collier

    George Collier Member

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    As Sirius Glass says, with different words, I came back to this, thought about something else - see if the take-up mechanism is lifting or distorting that right end (looking from the back) when advancing, and leaving it that way. Does this happen on every frame?
     
  5. werra

    werra Subscriber

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    Is this present on all rolls? The film is not wound tightly over the rollers?
    Or maybe the lens and shutter have been removed and were not put back correctly. Or, on the worst case, the lens has been disassembled and reassembled incorrectly.
    Front standard not locking correctly or maybe wobbling. Where is the shutter release, on the body or on the lens?.

    Such a fuzziness should be apparent even on ground glass, using the loupe. A bit of work of course due the tiny image.
     
  6. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

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    May be you did not strech the film between right roll and left roll. You need to play with winding knob to strech the film before exposing. It must be tight but dont rip the film also.
    My Leica had it , I went a famous repairman 400 kilometers far and he hold the body and pressed the plate with two fingers and everything sat where it might be sit before.
    Press the plate with two first fingers and check from the side , does it parallel to film and cover.

    Good luck ,

    Umut
     
  7. jtcliff

    jtcliff Subscriber

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    Thanks everyone. The standard is rock solid, the film is always wound tightly. I believe the back plate is allowing a movement of the film further away from the lens at the take up side. I have applied a little pressure and it moved. Another test roll I think.
    Once again, I appreciate your ideas and suggestions.
     
  8. jtcliff

    jtcliff Subscriber

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    Correction NOT the left take up side but the right, new roll side.
     
  9. jnanian

    jnanian Advertiser

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    hi there

    take a piece of waxedpaper and tape it on the film gate / place where your film would sit to be exposed.
    open your shutter up / bulb, and get a loup and focus your camera and see if with the stretched tight
    waxed paper the image is sharp from edge to edge. if it isn't ... your lens is off-kilter
    if it is sharp from edge to edge it might be something like a roller or pressure plate not being right ..

    and you need to have it straightened, unless, you want to use that affect as an effect and have it part of your signature :smile:

    good luck !
    john
     
    Last edited by a moderator: Dec 9, 2012
  10. rbender

    rbender Subscriber

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    I had a similar problem and it turned out to be the pressure plate not being flat
     
  11. Nicholas Lindan

    Nicholas Lindan Advertiser

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    I am not familiar with the Perkeo, but on other 120 folders the film runs over a set of needle rollers on either side of the film frame: keeping the film tight against these rollers is a large part of what keeps the film flat. There is usually a leaf spring that rubs against the film feed roll to provide tension as the film is wound on. If the spring is weak or missing, or if one of the rollers has gone missing, then you might see the problems you have described.

    Another common problem area are the leaf springs at the back of the pressure plate. They are usually slotted and slip under the heads of a set of rivets. If a spring has come unsprung then the pressure plate won't work correctly. Also, if these springs have become weak there can be problems.

    Often bending the spring back a little bit will restore things to good order.
     
  12. ic-racer

    ic-racer Member

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    That is a pretty good image from an old folder. You need to stop that down to get the edges sharper (if that is what you want). One side is worse than the other because when it unfolds, the lens and film are not parallel. You can try to fiddle with it, but there is no comparison with a Rolleiflex TLR, with its rigid box-like construction that keeps lens and film parallel. Even if you did get it aligned, the lens is still not very sharp at the edges. I'd just use it as it is and get a better camera if you want sharp corners.
     
  13. John cox

    John cox Member

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    Could also be an issue with film flatness on the scanner if you are scanning.
     
  14. elekm

    elekm Member

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    It's possible the camera was dropped to a carpeted floor at some point, knocking the lens standard out of square ever so slightly. And with a carpeted floor, there wouldn't be obvious signs of damage.

    However, I agree with others to first make sure the pressure plate has enough pressure to keep the film flat. The waxed paper idea across the film plane is a good one, too.
     
  15. jtcliff

    jtcliff Subscriber

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    Once again thank you all for the solid advice. On checking the pressure plate I noticed it was not lying parallel to edges of the "door". Manipulation caused the leaf springs to free up in their slots and the plate looks in a better position. I will also work on the leaf springs controlling the film roll.
    This is a great site. Thanks.
     
  16. jtcliff

    jtcliff Subscriber

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    Conclusion

    Folks, it WAS the back plate. See the two attachments below. Left is after back plate adjustment. Right is before adjustment.
     

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  17. Sirius Glass

    Sirius Glass Subscriber

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    Yep, you nailed it.